The present invention relates to a semiconductor memory and, more particularly, to a technique which may effectively be applied to, for example, a micro-programmable ROM (Read-Only Memory) which may be incorporated in a digital processing device that adopts the microprogram system.
Digital processing devices that adopt the micro-program system are described, for example, in "Micro-programming and Its Application", Sangyo Shuppan Kabushiki Kaisha, May 20, 1974, pp. 48 to 51.